On the subject of the various Let's Send CoD To Asia arguments, I think it would be an interesting move, with one massive caveat.
The really interesting stuff (the various sackings of Singapore, the wandering around the jungles of Burma knocking off Japanese soldiers on pushbikes with a knife, a couple of hand grenades and a pistol, that sort of thing) just won't sell in America, because 1) it doesn't fit into the conventional FPS mould, although that last part would work brilliantly as a sort of Hitman-style assassination game (think Haze but with the second half done properly), and 2) because it doesn't directly involve Americans, it being the British Empire's outposts in the Far East fighting off the Japanese. And if it won't sell well in America then no bugger'll do it, as we are all aware.
As for a futuristic setting, again it could work but the Americans won't buy into it - partly because of the aforementioned comparisons to Crysis and Halo and the rest of the soft-as-butter scifi shooty crapwave that threatens to drown the genre. If they want to make it interesting they only have two realistic options.
Choice A is to go for near-future battling insurgencies in Africa, the Middle East and possibly even the bits of the old Soviet Union that are really totally separate from Russia, really they are, honest. This would work as a sort of Mass Effect-style thing but with Afghan tribesmen and African warlords replacing all the starships and glowy aliens. An interesting idea would be to rip off elements of Joe Haldeman's Forever Peace, with the Americans piloting remotely-operated near-indestructible drones and trying not to go insane from the pain and mental anguish that doing such a thing would cause for the combatant, and brokering peace with the various factions by bribing them with a remotely stable food supply. Perhaps at low 'health' the player experiences the onset of madness, like wonky vision, a slow removal of control, lowered accuracy, altered perceptions of reality, that sort of thing.
Choice B is harder to implement and bloody difficult to sell without resorting to the "It's a new CoD, buy it anyway, sheeple" school of marketing. This route takes one into the far, far future, but the twist is it's hard SF. This means: few aliens, and those are likely of the Starfish Alien variety. No FTL. No Zero Point Energy. Very little in the way of physical battles, and very little in the way of battles in general, but when war comes, it comes BIG. A weird, unknowable alien threat comes roaring into the outskirts of known space and proceeds to piss on humanity's breakfast cereal. New theatres are opened up: boarding actions, cyberwarfare (which might get a bit meta), space combat, infiltration, you name it. For a little further reading, check out Orion's Arm, which would be a very interesting setting to nick stuff from.
All in all, the idea has potential, but only as an artistic work rather than an outright money spinner.
Whether this is a good or bad thing is entirely at your discretion.